Tykerb also known as Lapatinib is a new breast cancer drug currently undergoing for breast cancer patients who have over expression of HER2 gene. A recent clinical study has demonstrated that Lapatinib is effective in treating patients with breast cancer who have HER2 amplification and are no longer responding to Herceptin, which is the most common drug used in that setting.

About twenty percent of patients with breast cancer may have over expression of the HER2 gene and these patients commonly do worse in comparison to breast cancer patients who do not possess HER2 gene over expression. Herceptin is a drug that is routinely used in patients with breast cancer who have HER2 gene over expression. However with ongoing therapy the cancer might acquire resistance towards herceptin and in that case the drug loses its effectiveness to treat that patient with breast cancer. Tykerb is effective in such patients who are resistant to herceptin. In a recent clinical trial Lapatinib has shown to double the time for progression of cancer to 8.5 months compared to chemotherapy alone. All patients in this study, had amplification of HER2 gene and had breast cancer progression while receiving herceptin therapy. Tykerb causes anticancer property by blocking two biochemical pathways that involve ErbB1 and ErbB2 and has lesser side effects when compared with herceptin.

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